/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright © 2020 Keith Packard
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "stdio_private.h"

char * __disable_sanitizer
vasnprintf(char *str, size_t *lenp, const char *fmt, va_list ap)
{
	struct __file_str f = FDEV_SETUP_STRING_ALLOC_BUF(str, *lenp);
	int i;

	i = vfprintf(&f.file, fmt, ap);

        /*
         * Use fputc to append a NULL to handle
         * buffer overflow cases
         */
	if (i >= 0) {
                if (fputc('\0', &f.file) < 0)
                        i = EOF;
        }

        char *ret = POINTER_MINUS(f.end, f.size);

        if (i >= 0) {
                *lenp = (size_t) i;
                /* Try to shrink the buffer */
                if (f.alloc) {
                        char *s = realloc(ret, i + 1);
                        if (s)
                                ret = s;
                }
        } else {
                if (f.alloc)
                        free(ret);
                ret = NULL;
        }
        return ret;
}
